Drain & Sewer
Lateral Line
A lateral line is the section of sewer pipe that runs from a private property to the municipal sewer main in the street. It is the homeowner's responsibility — not the city's — to maintain and repair the lateral line from the house to the connection at the city main (and sometimes including the connection point itself, depending on the municipality). Lateral lines are typically 4 inches in diameter and run 20–100 feet depending on how far the house sits from the street.
Lateral lines are susceptible to the same problems as any underground pipe: root intrusion, joint separation from soil movement, corrosion, and sags or bellies where debris accumulates. Because homeowners often don't realize they own the lateral line, they are sometimes caught off guard when their city tells them that a sewer backup or blockage in their lateral is their problem and their expense to fix.
What This Means for You
Know where your lateral line runs and who is responsible for it in your municipality. Most cities make the homeowner responsible for the lateral from the house to (and including) the tap connection at the main. Before buying a home, ask whether the lateral has been inspected — camera inspection of a lateral is a reasonable due-diligence item on older properties.
Related Terms
Sewer Line · Cleanout · Tree Root Intrusion · Pipe Belly (Sag) · Camera Inspection